How long does a 400 watt HPS last? And what goes out first?

I know the bulbs are rated for 24,000 hours, which would equal 2,000 twelve hour days, which is a ton.

What are peoples experience with their older setups? Do the ballasts go out or do they last a long time like fluorescent ballasts? Do the bulbs dim and blow out? What kind of problems do people have with a typical 400 watt HPS?

If it is an old magnetic ballast and well built with good components, it'll last almost forever. Keep it cool, I run mine with open cases in an area where they have no chance of getting wet and they'll probably outlive me. Any decent magnetic ballast is reliable, if nothing else. The heat difference between the 400, 600 and 1000W are pretty substantial, I'd guess that alone would make the 400 the longest lasting of the bunch. The first real lamp I ever bought was a used 400 that came from a streetlight. It looked like it was from the early 80s and it still worked like a charm. I guess the point I'm getting at is: I don't think you'll have many issues with it.

Thanks. This is what I thought. From everything I've heard and read, 400 watt is the sweet spot. I've even heard the big growers prefer two 400 watt to one 1000 watt. They get better coverage with multiple lower watt setups.